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The present invention generally relates to a method and process for producing an improved milk replacer. More particularly, the present invention relates to a method and process for producing a milk replacer with improved physical characteristics, such as enhanced particle strength and fat stability, and improved hydration characteristics.
Calves at birth have underdeveloped stomachs and lack the ability to digest fibrous feeds. The only functional stomach compartment of newborn calves is the abomasum. Thus, newborn calves are fed a liquid diet that, upon ingestion, is naturally channeled directly to the abomasum. Many milk-based feeds will clot in the abomasum with the aid of enzymes, such as rennin and pepsin, that are present in the abomasum. Rapid separation of the clot from liquid whey protein and lactose components of the feed then follows in the abomasum, with subsequent digestion of the clot, liquid whey protein, and lactose components in the duodenum.
Lactose, under the action of lactase, yields galactose and glucose, which produces energy for growth; laying down of muscle and fat; and body temperature maintenance that is necessary for metabolical reactions. The clot, consisting primarily of protein and fat, is broken down in the duodenum by proteases and lipases into amino acids and fatty acids, respectively. Amino acids and fatty acids that are absorbed in the duodenum are used to maintain biological processes, repair tissues, and form blood. Sugars, amino acids and fatty acids in the duodenum also help sustain and build up the microbial population in the newborn calves for proper digestion of a fibrous diet.
It is well known that feeding of newborn calves with milk replacers is an acceptable form of dairy herd management that offers various advantages. For example, milk replacer can save the dairy producer money depending upon the amount of milk replacer substituted for mother""s milk in newborn calf nourishment. Milk replacers also permit flexible modification of the nutrient mix fed to newborn calves to supply unique nutrients to newborn calves that are not normally present in whole milk produced by mother cows. Weaning newborn calves off whole milk also frees up the mother cows to perform other dairy-based operations, such as providing milk for human consumption or conversion to more valuable dairy products, such as cheese.
Milk replacers may be in liquid or dry powder form. Powdered milk replacers cost less to transport than liquid milk replacers, which helps to improve the overall efficiency of dairy production. Powdered milk replacers are also less likely to support microbial growth during storage than liquid milk replacers. Powdered milk replacers thus offer various benefits compared to liquid milk replacers.
Milk producers want powdered milk replacers that are stable upon rehydration; undergo little or no fat separation, prior to, during, or after hydration; are easily rehydrated in hot or cold water; have an optimum fat particle size distribution that aids in digestion by the calf; and exhibit little, if any, clumping during storage prior to hydration. To fulfill these desires, milk replacer manufacturers typically seek to obtain the following reconstitution properties in powdered milk replacers: high particle wettability, high dispersability, low sedimentation tendencies, and stability of the fat-in-water emulsion formed upon rehydration.
Wettability refers to the rate at which a particle of powder is surrounded by the rehydration medium and sinks away from the liquid surface. Dispersability is the degree to which the powder particles go into solution, while sedimentation is the degree to which the powder particles precipitate as a solid on the bottom of the mix vessel during or after rehydration. A stable liquid emulsion may be characterized as a homogenous system of two or more immiscible liquids. In a liquid emulsion, one of the liquids is homogeneously dispersed in another of the liquids with the assistance of an emulsifier. The emulsifier helps stabilize the liquid emulsion system. Since powdered milk replacers that contain a fat component must be rehydrated in water prior to use, a stable fat-in-water emulsion is a desired property in milk replacers.
It is challenging to produce powdered milk replacers with an optimum balance of these reconstitution properties since each property may compete with one or more of the other properties. For example, high wettability may result high sedimentation tendencies. Therefore, in pursuit of these optimized reconstitution properties, powdered milk replacers are sometimes agglomerated to modify particle size and enhance rehydration characteristics. Agglomeration is a process in which small particles are fused into larger particles, or agglomerates. The larger particle size that results from agglomeration tends to reduce the tendency of product caking, prior to hydration, and tends to improve rehydration characteristics for component particles of the agglomerate, as compared to the rehydration characteristics for component particles that are not agglomerated.
Current powdered milk replacers, though helping to advance the knowledge base regarding reconstitution properties, have not fully achieved an optimum combination of reconstitution properties. Furthermore, current production techniques for manufacturing powdered milk replacers do not consistently and efficiently produce powdered milk replacers having fully satisfactory reconstitution properties. In addition, equipment currently used to produce powdered milk replacers does not accommodate flexible incorporation of liquid agglomerating aids, such as water, during the agglomeration process. Therefore, an urgent need presently exists for an improved powdered milk replacer that better optimizes the reconstitution properties and more efficiently transfers needed nutrients to newborn calves and for an improved technique of producing powdered milk replacer that is more efficient, flexible, and cost-effective than present dairy industry practice.
The present invention includes a method of producing a milk replacer product that includes creating a pattern of air flow in a mixing zone of a mixer, gravity feeding a powdered nutritional composition into the mixing zone, applying an agglomerating aid to the particles of the powdered nutritional composition in the mixing zone, where the agglomerating aid, in combination with the pattern of air flow, is effective to cause particles of the powdered nutritional composition to stick together and form agglomerates, and drying the agglomerates to form the milk replacer product. The present invention further includes a milk replacer product and a method of agglomerating a powdered nutritional composition to form a milk replacer product.